Structural, optical, dielectric, and electronic properties of cobalt-doped SnO₂ nanoparticles for anode applications in energy devices

Lithium-ion batteries (LIBs) play a key role in energy storage, powering electronics, and grid systems. Research on high-efficiency, cost-effective anode materials like tin dioxide (SnO₂) aims to improve electrochemical properties and stability. Doping SnO₂ with cobalt enhances its performance by addressing defects. Understanding their structural and optoelectronic properties is crucial for advancing and optimizing their applications. This manuscript presents a systematic study on the synthesis and characterization of cobalt-doped tin oxide nanoparticles (Co-doped SnO₂ NPs) <i>via</i> a sol-gel method with cobalt concentrations ranging from 0% to 15 wt%. The research focuses on their structural, optoelectronic, dielectric, and electronic properties, with a particular emphasis on their potential applications as advanced anode materials for lithium-ion batteries (LIBs). Advanced characterization techniques including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and UV-vis spectroscopy revealed that cobalt doping induces significant structural and optical modifications. Notably, the bandgap of Co-doped SnO₂ NPs narrowed from 3.48 eV (undoped) to 3.15 eV (15 wt% Co), enhancing electrical and optical conductivities and light absorption. Furthermore, Co-doping of SnO₂ NPs improves several key electronic properties, such as plasma frequency, Penn energy, and Fermi energy, which can contribute to improved conductivity, stability, and charge retention in LIB applications. The increased electron density and polarization observed with higher cobalt concentrations suggest that Co-doped SnO₂ NPs are a promising material for use in LIBs, particularly as an anode material, where efficient electron and ion transport is critical for high-performance energy storage.